Complex cognitive functions such as attention require network level neural interactions that are not well understood. A variety of recent studies has found evidence that neural synchrony within and across brain structures reflects perceptual, behavioral, and cognitive functions. Abnormal patterns of neural synchrony have been cited in neurological diseases such as schizophrenia, Parkinson's disease, epilepsy, autism, and Alzheimer's disease, but the information maintained or disrupted by this coherent activity is not well characterized. We will study the role of neural synchrony within the context of visual spatial attention, which places high demands on the brain's ability to selectively process behaviorally relevant information. We have trained monkeys on a behavioral task in which they must maintain fixation and covertly attend to a peripheral location to detect a change at that location while ignoring distracters. Preliminary results show persistent activity in the frontal eye field (FEF) in the prefrontal cortex that is able to predict task performance. In Aim 1, we will test the extent to which synchrony in the FEF provides a signature for attention by recording and analyzing single-unit, multi-unit, and local field potential (LFP) activity in the FEF during the task. In Aim 2 we will examine how sustained attention affects the degree of coupling between the FEF and extrastriate visual area V4. We will collect simultaneous recordings from the FEF and V4 while the monkey performs the change detection task. Using different coupling metrics, we will test whether interactions between the two areas can provide a better predictive measure of the monkey's behavior than activity in either area alone. The proposed research will provide insight into the functional role of synchrony and may have clinical implications for disease biomarkers.